The present invention relates to a radiation permeable table insert, used in the reclining surface of a patient's radiation therapy couch.
Radiation therapy couches are conventional and typically used to hold the patient in a substantially rigid position while the patient is being exposed to a radiation source. Typically the radiation source is mounted above the couch and movable around the couch so that the patient can be exposed to radiation from all possible angles, all to allow for purposefully directed radiation at the precise tumor site needed in order to destroy the tumor and minimize the exposure to healthy tissue.
Such treatment couches usually have open windows or frame supports at both ends providing a passageway for radiation to be directed through a table insert at the patient's tissue. This prevents having any of the radiation attenuated or absorbed by the couch itself. Typical radiation therapy couches are well known and are made by companies such as Siemen's.
It is important for the accuracy of calculations of the radiologist and the directional precision of the instrument that the patient's body is maintained in a rigid, properly aligned position. The correct alignment of the treatment rays must be maintained, otherwise needless harm to good body tissue may occur or dose attenuation may occur.
Currently manufacturers are supplied with rigid frames, often made of aluminum, to provide a four-sided framework with a grid, mounted in the frame similar to the way nylon strings are mounted in a tennis racket. This frame is then inserted into its proper window position in the radiation therapy couch. In this way there is a radiation transparent window in the couch.
Numerous problems exist with current frames as they are used. In the first instance those frames, if made of material such as aluminum, block some of the rays and may attenuate the radiation, making the dose inaccurate. This is especially true if the emitting apparatus is mounted in a position such that the emitted radiation is along a line that would normally pass through the framework of the tray.
In addition to the framework often blocking some of the emitted radiation, many of the materials used as the grid or network such as nylon will sag after a few uses. As a result the proper alignment of the patient with regard to the x-ray emitting apparatus, is no longer maintained.
Particularly troublesome in the current times when x-ray emitting patterns and doses are mathematically calculated for 3-dimensional treatments, various angles on the 360.degree. position around the tumor point are often impossible to use since the couch insert frame itself blocks some of the dose if otherwise desired angle is used.
It therefore can be seen that there is a continuing need for development of radiation therapy table inserts that will not sag, that will maintain the body in a precise fixed position, and that will allow substantial freedom to the x-ray operator to orient the rays at as many angles as possible around 360.degree. of the patient's tumor location. Also there is always a need for uninterfered lateral x-ray access. This invention has as its primary objective the fulfillment of these needs.